Spark-plug.



R. HUGHES.

SPARK PLUG.

APPLICATION FILED JUNEEyIQlG.

Patehted Jan. 2, 1917.

pazerl /zgz es A 770RIVEYS ROBERT HUGHES, F MOUNT VERNON, NEW YORK.

SPARK-PLUG.

Specification of Letters Patent.

Patented; Jan. 2, 1917.

Application filed June 6, 1916. Serial No. 101,907.

To all whom it may concern Be it known that I, ROBERT HUGHES, a citizen of the United States, and a resident of Mount Vernon, in the county of Westchester and State of New York, have invented certain new and useful Improvements in Spark-Plugs, of which the fol lowing is a specification.

My invention relates to spark plugs for internal combustion engines, and the main objects thereof are to provide means for protecting the porcelain from cracking, to provide means whereby the plug may be cleaned without removing the same from the cylinder, as well as the contact points, to

provide means whereby new contact points may be utilized at will without removing the plug from the cylinder, and to provide means whereby the spark gap may be adzojusted at will without removing the plug from the cylinder.

My invention is fully described in the following specification, of which the accompanying drawings form a part, in which like characters refer to like parts in each of the views, and in which Figure 1 is an elevationof my spark plug; Fig. 2 is a central longitudinal section therethrough, with the parts in position for-use; Fig. 3 is an elevation, partly in section, showing the manner of clearing the plug of soot; Fig. 4 is a fragmentary view showing the manner of cleaning the contact points; and Fig. 5 is a bottom plan view thereof.

Referring to the drawings, 6 represents a cylindrical body portion threaded at 7 for engagement with the cylinder of an engine, having a bore of two diameters to provide a shoulder 8, 'and recessed in the top as shown at 9 to provide a seat for a porcelain collar 10 within which a porcelain tube 11 is slidably mounted and in turn formed of two diameters to fit within the bore of the body member 6 and having a shoulder greater diameter than the porcelain tube 11, a coil spring 17 being interposed between said nut and the top of the collar 10 of Suficient strength to resist the suction stroke of the engine piston and normally holding the porcelain tube 11 in uppermost position but permitting depression of said tube 11 to carry the lower end thereof out of the soot chamber in the bottom of the body member 6 to scrape any soot from the interior wall of said body member, as shown in Fig. 3. Also threaded on the upper end of the metal tube 14 is a nut 18 for holding a terminal 19 against the nut 16, the nut 18 having an upwardly directed projection 20' thereon provided with a tapped bore 21 engaging a threaded portion of the center pole 22 hooked at its lower end to provide a point 23 adjustable toward or from the lower edge 24 of the body member 6 to provide a spark gap, and I also provide a lock-nut 25 at the upper end of this center pole and slot the pole at 26 for screw-driver engagement to adjust the spark gap. It will be noted that the porcelain tube 11 is assembled upwardly through the body member 6 instead of downwardly as in the conventional plugs and said tube is normally held within the body member 6 for protection, and this arrangement permits longitudinal expansion of said tube when heated and thereby overcomes the cracking thereof as is common in plugs now known to me, a space being provided, in use, between the tube 11 and nut 16 which does not loosen the tube as the spring tension on the nut 16 holds 'the shoulders 8 and 12 together through the medium of the metal tube 14 and shoulders 13 and 15.

By means of the nut 16 the center pole 22 may be rotated to carry the point 23 to any desired portion of the lower edge 24 of the body member 6, thus providing the full equivalent of a multitude of points and, if

the nuts 18 and 25 be jointly unscrewed the former rises on the threaded end of the metal tube 14 and thus brings the point 23 against the lower edge 24 of the body mem} her and, if the large nut 16 be now rotated, the point 23 is scraped over the surface 24 and thus cleans said surface as well as itself. This joint movement of the nuts 18 and 25 ,does not affect their relationship with the center pole 22 and, when said nuts are again tightened, the point 23 is again moved away from the surface 24 to provide a spark gap of previously obtained.

From the foregoing it will the plug need not be removed from the be seen that the same adjustment as had engine for adjusting the spark gap, for brightening the points, for adjusting to new points, or for scavenging the soot chamber in the bottom of the body member, thereby insuring maximum efficiency to the plug.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A spark plug, comprising a. body member of conductive material, an insulating tube slidable therein, a spring for resisting such movement, and a center contact pole in said tube, said tube fitting the interior of the body member whereby it will clear the latterof soot when manually depressed against the action of said spring.

2. A spark plug, comprising a body'member having a soot chamber in the bottomthereof, aspring controlled insulatingtube slidably held in said body portion and closely fitting the interiorthereof whereby it will clear the latter of soot when manually depressed against the action of said spring, a center contact pole in said tube, andmeans for externally rotating said pole to carry the point at its lower end to different points at the lower end of said body member to present new sparking points.

3. A spark plug, comprising a body member having an unbroken lower edge perpendicular to its'longitudinal axis, an insulating tube therein, a center contact pole in said tube, having a hooked lower end in juxtaposition with said lower edge, external means for carrying said end against said edge and external means for rotating said pole whereby said end and .edge may be cleaned. v

' 4. A spark plug, comprising a body member having an unbroken lower edge perpendicular to its longitudinal axis and having a bore of two diameters to form a shoulder, an insulating'tube of two diameters slide ably fitted within said body member and having a shoulder bearing against said first named shoulder, a spring for yieldingly holdingsaid shoulders together, a hooked center contact pole .inflsaid ;tube, and a nut threaded on said pole foradjusting the lower end thereof toward or from said body mem ber to provide a' desired spark gap between itself and said body member.

r 5. A spark plu comprising a body member having an-un rokenlower edge perpendicularto its longitudinal axis and. having a bore of two diameters to form a shoulder, an insulating tube of-two diameters slidably fitted within said body member and having ashoulder bearing against said first named shoulder, a spring for yieldingly holding said shoulders together, a-hooked center contact pole slidable and rotatable in said tube,

a nut threadedon said pole for adjusting the lower end thereof toward or from said body member to provide a desired spark gap between itself and said body member, and means for rotating said pole to carry the hooked end of said pole into difierent radial positions with respect to said body member to provide new sparking points.

6. A spark plug, comprising a body member having an unbroken lower edge perpendicular to its longitudinal axis and having a bore of two diameters forming a shoulder, an insulating tube of two diameters forming a shoulder slidably fitted within said body member, a spring for yieldingly holding said shoulders together, a hooked center contact pole in said tube, and a nut threaded on said pole for adjusting the lower end thereof toward or from said body member to provide a desired spark gap adjustment, said tube being manually depremible to clear the inbody member in said cleansing operation to prevent a spark during said operation.

7. A spark plug, comprising a body member having a bore oftwo diameters forming a shoulder, an insulating tube slidably fitted into said bore and having a shoulder thereon normally resting against said first named shoulder, a metal tube within said insulating tube, means for preventing upward movement thereof in said insulating tube, a nut threaded on said metal tube above said insulating tube, aspringbearing on said nut to maintain said shoulders in yielding engagement, and a center contact'pole adjust ably arranged within said metal tube, said spring maintaining said shoulders in engagement with said nut spaced from the upper end of said insulating tube to permit expansion and contraction of said insulating tube.

8. A spark plug, comprising a body member having a bore of two diameters to form a shoulder, an insulating tube fitted into said bore and having a shoulder thereon resting against said first named shoulder, an insulating collar seated above said body member and encircling said tube, av metal tube within said insulating tube, means for preventing upward movement thereof, a nut threaded on the upper end thereof, a spring interposed between said nut andsaid collar, a supplemental nut in threaded engagement with the upper end of said metal tube and having a reduced threaded bore, and a center contact pole inv threaded engagement ROBERT HUGHES. 

